The present invention relates to a resist processing apparatus for coating a substrate with a resist, sending the substrate to an aligner and developing the substrate received from the aligner, and a measuring method therein.
In a photo-resist process of semiconductor device fabrication, a resist solution is coated on a surface of a substrate such as a semiconductor wafer, which is called a wafer hereinafter, to form a resist film. After the predetermined pattern is exposed on the resist film, the substrate is supplied with a developing solution and developed. A resist processing apparatus and an aligner have been used so far in a series of the above processes.
The resist processing apparatus is provided with processing units which individually perform a series of processes necessary for coating and developing, that is, an adhesion unit, a coating unit, a thermal processing unit, a developing unit and the like. An adhesion unit performs adhesion treatment to improve resist fixing. A coating unit coats a substrate with resist solution. A thermal processing unit heats a substrate coated with resist solution to cure a resist film. Another thermal processing unit heats an exposed substrate at the predetermined temperature. A developing unit develops an exposed substrate. A carrier unit is used for carrying a wafer between each processing unit or carrying a wafer into and out from each processing unit, a carrier unit, for example, being able to move while holding a wafer.
Temperature control in the above thermal processing unit is very important. Poor temperature control causes poor film thickness and poor developing of resist. Therefore, not the temperature in a thermal processing unit, but the real temperature of a wafer in a thermal processing unit may be measured using, for example, a wafer in which a thermocouple is buried.
More concretely, when measurement is necessary, the real operation of the resist processing unit is suspended and a cover of the thermal processing unit is opened. After the thermocouple wafer is placed in a position in which wafers are heat-treated in the thermal processing unit, the thermocouple wafer is heat-treated in an ordinary heat treatment. In a temperature measuring apparatus, the temperature is measured through the thermocouple buried in the thermocouple wafer and a measured result is processed. That is, the thermocouple wafer is not measured in the thermal processing unit. This is because a plurality of cables coupled between the thermocouple wafer and the temperature measuring apparatus interfere with normal shutting of the cover in the thermal processing unit. Additionally, a setting error cannot be prevented because the thermocouple wafer is manually placed in the thermal processing unit.
A series of the above processes is, however, performed manually so that it is difficult to exactly measure the temperature of a heat-treated wafer.
Moreover, the manual measurement described above requires suspension of the real operation for a considerable time, which results in a loss in apparatus operation time.
There is another disadvantage that the above measurement may lead to some human error. For example, a thermocouple wafer may be dropped from tweezers and be broken.